What are factors that effect my wireless coverage area?

Metal studs in walls, concrete fiberboard walls, aluminum siding, foil-backed insulation in the walls or under the siding, pipes and electrical wiring, furniture, water

RF Interference from microwave ovens, Other wireless equipment, cordless phones, radio transmitters, other electrical equipment and pretty much anything that operates in the 2.4 GHZ range

Environmental factors: Weather conditions can have a huge impact on wireless signal integrity. Lightning, for example, can cause electrical interference, and fog can weaken signals as they pass through.